(from Sport and Travel From the Northland of Canada by David T. Hanbury, 1904, chapter VI "Life in an Eskimo Camp on Baker Lake") Read the passage carefully and then choose the correct answer.

... This passage saves a considerable distance, about twenty miles I should judge. The charts do not mark the point as a peninsula.

A phenomenon of these parts is the mirage, which is much more marked on some days than on others. It is observed on the larger lakes and along the coast particularly. Land which is only a short distance away appears suspended in mid-air, and great distortion takes place. Captain Santos informed me that owing to this peculiarity it is impossible to get good sights at sea.

The voyage up Chesterfield Inlet was slow and far from pleasant; the cold was severe, for although the thermometer never dropped even to zero, it was our first touch of winter cold, and was keenly felt. We had to sit still for twelve hours at a stretch, everything on board coated with ice and a cutting wind in our teeth. The whale-boat leaked so badly that every night it had to be unloaded and in the morning loaded afresh. This necessitated wading. We all had long sealskin boots luckily, but these would freeze stiff directly we left the water.

Which of the following is an example of a signal phrase?
much more marked on some days than on others
do not mark the point as a peninsula
sit still for twelve hours at a stretch
larger lakes and along the coast particularly